Recent progress in the superhard nanocrystalline composites: towards their industrialization and understanding of the origin of the superhardness

Recent progress is presented regarding the development of plasma induced CVD technique for coatings of non-planar and thick tools and of the understanding or the origin of the high thermal stability of the nanocrystalline TiN/amorphous Si3N4 superhard coatings up to 11000 degrees C. A chlorine free, combined plasma CVD and PVD technique was developed for the deposition of superhard nc-TiN/c-BN nanocomposites. These coatings are compatible with the majority of engineering materials, such as ferrous and aluminum alloys and others. Their hardness reaches 70 Gpa and elastic modulus E/(1-nu(2))approximate to 585 Gpa. An industrial production reactor was built which enables one to deposit such coatings on cutting tools. (C) 1998 Elsevier Science S.A. All rights reserved.